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Physical Sciences and Mathematics Commons™
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- Amino acid analysis, thermus thermophilus, principal component analysis, molecular dynamics, crystal structure, salt bridges biochemical simulations, extremophiles (1)
- Boundary layer, HONO, photolysis, urban atmosphere (1)
- Climate and earth system modelling, projection and prediction (1)
- Combustion conditions, photoenhanced uptake, laboratory systems, tyrosine oxidation (1)
- Communities of Practice, Karst, Caves, Information portals, Florida (1)
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- Environmental Management, Karst, Index, Human impact, Caves, Environmental Indicators (1)
- Florida, Karst Index, Human impact, Environmental indicators (1)
- General circulation model, submodel system messy, sulfate production, dry deposition, sulfuric acid, climate model (1)
- Nitrous acid HONO, heterogeneous reaction, aerosol particles, quantum yields, photochemical production (1)
- Nitrous acid HONO, simulated vertical profiles, submodel system messy, boundary layer, urban atmosphere, forest canopy, air quality, nitric acid (1)
- Pollution, Caribbean, heavy metals, Fiddler crab, Black mangrove (1)
- Positive semidefinite matrices, integer-diagonal, trace (1)
- Small island developing states, Sustainable development, Index, Trinidad & Tobago, Climate change (1)
- Tropical rain forest, isoprene oxidation mechanisms, hydroxyl radicals, urban atmosphere, nitrous acid (1)
- Volatile organic compounds, nitrous acid HONO, aerosol formation, humic acid (1)
- Volatile organic compounds, nitrous acid HONO, urban atmosphere, boundary layer, tropospheric degradation (1)
Articles 1 - 16 of 16
Full-Text Articles in Physical Sciences and Mathematics
Bioaccumulation And Biomagnification Of Potential Toxic Elements (Ptes): An Avicennia Germinans–Uca Rapax Trophic Transfer Story From Jobos Bay, Puerto Rico, Michael Martinez-Colon, Henry Alegria, Hatice Kubra-Gul, Ashley Huber, Perihan Kurt-Karakus
Bioaccumulation And Biomagnification Of Potential Toxic Elements (Ptes): An Avicennia Germinans–Uca Rapax Trophic Transfer Story From Jobos Bay, Puerto Rico, Michael Martinez-Colon, Henry Alegria, Hatice Kubra-Gul, Ashley Huber, Perihan Kurt-Karakus
USF St. Petersburg campus Faculty Publications
In southern Puerto Rico along the coastline bordering the Jobos Bay National Estuarine Research Reserve, environmental encroachment has exposed mangrove forest to different sources of pollution. Potentially toxic element concentrations from the F1Tess (exchangeable), F4Tess (oxidizable), mangrove leaf litter (MLL), and fiddler crab whole body soft tissue were analyzed to assess the fate and transport of pollutants from the environment and its transition into flora-fauna via trophic transfer. Geo-accumulation factor values suggest the bay has experienced limited to no pollution when combining the concentrations of potentially toxic elements extracted from the F1Tess and F4Tess sediment fractions. These geochemical sedimentary compartments …
A Trace Bound For Integer-Diagonal Positive Semidefinite Matrices, Lon Mitchell
A Trace Bound For Integer-Diagonal Positive Semidefinite Matrices, Lon Mitchell
USF St. Petersburg campus Faculty Publications
We prove that an n-by-n complex positive semidefinite matrix of rank r whose graph is connected, whose diagonal entries are integers, and whose non-zero off-diagonal entries have modulus at least one, has trace at least n + r-1.
Crystal Structure Of Thermus Thermophilus Methylenetetrahydrofolate Dehydrogenase And Determinants Of Thermostability, Fernando Maiello, Gloria Gallo, Camila Coelho, Fernanda Sucharski, Leon Hardy, Martin Würtele
Crystal Structure Of Thermus Thermophilus Methylenetetrahydrofolate Dehydrogenase And Determinants Of Thermostability, Fernando Maiello, Gloria Gallo, Camila Coelho, Fernanda Sucharski, Leon Hardy, Martin Würtele
USF St. Petersburg campus Faculty Publications
The elucidation of mechanisms behind the thermostability of proteins is extremely important both from the theoretical and applied perspective. Here we report the crystal structure of methylenetetrahydrofolate dehydrogenase (MTHFD) from Thermus thermophilus HB8, a thermophilic model organism. Molecular dynamics trajectory analysis of this protein at different temperatures (303 K, 333 K and 363 K) was compared with homologous proteins from the less temperature resistant organism Thermoplasma acidophilum and the mesophilic organism Acinetobacter baumannii using several data reduction techniques like principal component analysis (PCA), residue interaction network (RIN) analysis and rotamer analysis. These methods enabled the determination of important residues for …
Climate Policy Implications Of Nonlinear Decline Of Arctic Land Permafrost And Other Cryosphere Elements, Dmitry Yumashev, Chris Hope, Kevin Schaefer, Kathrin Riemann-Campe, Fernando Iglesias-Suarez, Elchin Jafarov, Eleanor J. Burke, Paul J. Young, Yasin Elshorbany, Gail Whiteman
Climate Policy Implications Of Nonlinear Decline Of Arctic Land Permafrost And Other Cryosphere Elements, Dmitry Yumashev, Chris Hope, Kevin Schaefer, Kathrin Riemann-Campe, Fernando Iglesias-Suarez, Elchin Jafarov, Eleanor J. Burke, Paul J. Young, Yasin Elshorbany, Gail Whiteman
USF St. Petersburg campus Faculty Publications
Arctic feedbacks accelerate climate change through carbon releases from thawing permafrost and higher solar absorption from reductions in the surface albedo, following loss of sea ice and land snow. Here, we include dynamic emulators of complex physical models in the integrated assessment model PAGE-ICE to explore nonlinear transitions in the Arctic feedbacks and their subsequent impacts on the global climate and economy under the Paris Agreement scenarios. The permafrost feedback is increasingly positive in warmer climates, while the albedo feedback weakens as the ice and snow melt. Combined, these two factors lead to significant increases in the mean discounted economic …
A Modeling Toolbox For Permafrost Landscapes, Irina Overeem, Elchin Jafarov, Kang Wang, Kevin Schaefer, Scott Stewart, Gary Clow, Mark Piper, Yasin Elshorbany
A Modeling Toolbox For Permafrost Landscapes, Irina Overeem, Elchin Jafarov, Kang Wang, Kevin Schaefer, Scott Stewart, Gary Clow, Mark Piper, Yasin Elshorbany
USF St. Petersburg campus Faculty Publications
No abstract provided.
A Sustainability Index For Small Island Developing States., Philip Van Beynen, Fenda A. Akiwumi, Kaya Van Beynen
A Sustainability Index For Small Island Developing States., Philip Van Beynen, Fenda A. Akiwumi, Kaya Van Beynen
USF St. Petersburg campus Faculty Publications
This paper proposes a novel approach to measuring the progress of Small Island Developing States (SIDS) towards sustainable development (SD) as set by the UN Sustainable Development Goals 2030. Currently, these goals do not provide adequate guidance on how countries might measure their progress towards sustainability. We use these goals and a subset of their targets to develop an index with concrete targets, through the use of pertinent sustainability indicators, that SIDS should aim to achieve a sustainable society. In addition to the three categorical pillars of sustainable development (social, economic, and environmental), we included the category Climate Change and …
Light-Induced Protein Nitration And Degradation With Hono Emission, Hannah Meusel, Yasin Elshorbany, Uwe Kuhn, Thorsten Bartels-Rausch, Kathrin Reinmuth, Christopher J. Kampf, Yafang Cheng
Light-Induced Protein Nitration And Degradation With Hono Emission, Hannah Meusel, Yasin Elshorbany, Uwe Kuhn, Thorsten Bartels-Rausch, Kathrin Reinmuth, Christopher J. Kampf, Yafang Cheng
USF St. Petersburg campus Faculty Publications
Proteins can be nitrated by air pollutants (NO2), enhancing their allergenic potential. This work provides insight into protein nitration and subsequent decomposition in the presence of solar radiation. We also investigated light-induced formation of nitrous acid (HONO) from protein surfaces that were nitrated either online with instantaneous gas-phase exposure to NO2 or offline by an efficient nitration agent (tetranitromethane, TNM). Bovine serum albumin (BSA) and ovalbumin (OVA) were used as model substances for proteins. Nitration degrees of about 1% were derived applying NO2 concentrations of 100 ppb under VIS=UV illuminated conditions, while simultaneous decomposition of (nitrated) proteins was also found …
Global And Regional Impacts Of Hono On The Chemical Composition Of Clouds And Aerosols, Yasin F. Elshorbany, P. J. Crutzen, B. Steil, A. Pozzer, H. Tost, J. Lelieveld
Global And Regional Impacts Of Hono On The Chemical Composition Of Clouds And Aerosols, Yasin F. Elshorbany, P. J. Crutzen, B. Steil, A. Pozzer, H. Tost, J. Lelieveld
USF St. Petersburg campus Faculty Publications
Recently, realistic simulation of nitrous acid (HONO) based on the HONO / NOx ratio of 0.02 was found to have a significant impact on the global budgets of HOx (OH + HO2) and gas phase oxidation products in polluted regions, especially in winter when other photolytic sources are of minor importance. It has been reported that chemistry-transport models underestimate sulphate concentrations, mostly during winter. Here we show that simulating realistic HONO levels can significantly enhance aerosol sulphate (S(VI)) due to the increased formation of H2SO4. Even though in-cloud aqueous phase oxidation of dissolved SO2 (S(IV)) is the main source of …
Impact Of Hono On Global Atmospheric Chemistry Calculated With An Empirical Parameterization In The Emac Model, Yasin F. Elshorbany, B. Steil, C. Bruehl, J. Lelieveld
Impact Of Hono On Global Atmospheric Chemistry Calculated With An Empirical Parameterization In The Emac Model, Yasin F. Elshorbany, B. Steil, C. Bruehl, J. Lelieveld
USF St. Petersburg campus Faculty Publications
The photolysis of HONO is important for the atmospheric HOx (OH + HO2) radical budget and ozone formation, especially in polluted air. Nevertheless, owing to the incomplete knowledge of HONO sources, realistic HONO mechanisms have not yet been implemented in global models. We investigated measurement data sets from 15 field measurement campaigns conducted in different countries worldwide. It appears that the HONO/NOx ratio is a good proxy predictor for HONO mixing ratios under different atmospheric conditions. From the robust relationship between HONO and NOx, a representative mean HONO/NOx ratio of 0.02 has been derived. Using a global chemistry-climate model and …
Comparisons Of Observed And Modeled Oh And Ho2 Concentrations During The Ambient Measurement Period Of The Ho(X)Comp Field Campaign, Y. Kanaya, A. Hofzumahaus, H. -P. Dorn, T. Brauers, H. Fuchs, F. Holland
Comparisons Of Observed And Modeled Oh And Ho2 Concentrations During The Ambient Measurement Period Of The Ho(X)Comp Field Campaign, Y. Kanaya, A. Hofzumahaus, H. -P. Dorn, T. Brauers, H. Fuchs, F. Holland
USF St. Petersburg campus Faculty Publications
A photochemical box model constrained by ancillary observations was used to simulate OH and HO2 concentrations for three days of ambient observations during the HO(x)Comp field campaign held in Julich, Germany in July 2005. Daytime OH levels observed by four instruments were fairly well reproduced to within 33% by a base model run (Regional Atmospheric Chemistry Mechanism with updated isoprene chemistry adapted from Master Chemical Mechanism ver. 3.1) with high R-2 values (0.72-0.97) over a range of isoprene (0.3-2 ppb) and NO (0.1-10 ppb) mixing ratios. Daytime HO2(*) levels, reconstructed from the base model results taking into account the sensitivity …
Learning And Engaging The Information Values Of A Karst Community Of Practice., Kaya Van Beynen, E S. Fleury
Learning And Engaging The Information Values Of A Karst Community Of Practice., Kaya Van Beynen, E S. Fleury
USF St. Petersburg campus Faculty Publications
The Communities of Practice model is an innovative means to explore a local knowledge community and how informal practitioners contribute to karst science. By exploring the information values, this article strategizes how the Karst Information Portal can promote trust, engagement, and expand the scientific understanding and protection of karst environments.
Oxidation Capacity Of The City Air Of Santiago, Chile, Yasin F. Elshorbany, R. Kurtenbach, P. Weisen, E. Lissi, R. Rubio, G. Villena, E. Gramsch, A. R. Rickard, M. J. Pilling, J. Kleffmann
Oxidation Capacity Of The City Air Of Santiago, Chile, Yasin F. Elshorbany, R. Kurtenbach, P. Weisen, E. Lissi, R. Rubio, G. Villena, E. Gramsch, A. R. Rickard, M. J. Pilling, J. Kleffmann
USF St. Petersburg campus Faculty Publications
The oxidation capacity of the highly polluted urban area of Santiago, Chile has been evaluated during a summer measurement campaign carried out from 8-20 March 2005. The hydroxyl (OH) radical budget was evaluated employing a simple quasi-photostationary-state model (PSS) constrained with simultaneous measurements of HONO, HCHO, O-3, NO, NO2, j((OD)-D-1), j(NO2), 13 alkenes and meteorological parameters. In addition, a zero dimensional photochemical box model based on the Master Chemical Mechanism (MCMv3.1) has been used to estimate production rates and total free radical budgets, including OH, HO2 and RO2. Besides the above parameters, the MCM model has been constrained by the …
Evaluation Of 1,3,5 Trimethylbenzene Degradation In The Detailed Tropospheric Chemistry Mechanism, Mcmv3.1, Using Environmental Chamber Data, A. Metzger, J. Dommen, J. Duplissy, A. S.H. Prevot, J. Kleffmann, Yasin F. Elshorbany, A. Wisthaler, U. Baltensperger
Evaluation Of 1,3,5 Trimethylbenzene Degradation In The Detailed Tropospheric Chemistry Mechanism, Mcmv3.1, Using Environmental Chamber Data, A. Metzger, J. Dommen, J. Duplissy, A. S.H. Prevot, J. Kleffmann, Yasin F. Elshorbany, A. Wisthaler, U. Baltensperger
USF St. Petersburg campus Faculty Publications
The degradation mechanism of 1,3,5-trimethyl-benzene (TMB) as implemented in the Master Chemical Mechanism version 3.1 (MCM) was evaluated using data from the environmental chamber at the Paul Scherrer Institute. The results show that the MCM provides a consistent description of the photo-oxidation of TMB/NO(x) mixtures for a range of conditions. In all cases the agreement between the measurement and the simulation decreases with decreasing VOC-NO(x) ratio and in addition with increasing precursor concentration. A significant underestimation of the decay rate of TMB and thus underestimation of reactivity in the system, consistent with results from previous appraisals of the MCM, was …
Light Induced Conversion Of Nitrogen Dioxide Into Nitrous Acid On Submicron Humic Acid Aerosol, K. Stemmler, M. Ndour, Yasin F. Elshorbany, J. Kleffmann, M. Ammann, B. D'Anna, C. George, B. Bohn
Light Induced Conversion Of Nitrogen Dioxide Into Nitrous Acid On Submicron Humic Acid Aerosol, K. Stemmler, M. Ndour, Yasin F. Elshorbany, J. Kleffmann, M. Ammann, B. D'Anna, C. George, B. Bohn
USF St. Petersburg campus Faculty Publications
The interactions of aerosols consisting of humic acids with gaseous nitrogen dioxide (NO2) were investigated under different light conditions in aerosol flow tube experiments at ambient pressure and temperature. The results show that NO2 is converted on the humic acid aerosol into nitrous acid (HONO), which is released from the aerosol and can be detected in the gas phase at the reactor exit. The formation of HONO on the humic acid aerosol is strongly activated by light: In the dark, the HONO-formation was below the detection limit, but it was increasing with the intensity of the irradiation with visible light. …
Application Of A Karst Environmental Disturbance Index In Hillsborough County., Philip Van Beynen, Nilda Feliciano, Leslie North, Kaya Van Beynen
Application Of A Karst Environmental Disturbance Index In Hillsborough County., Philip Van Beynen, Nilda Feliciano, Leslie North, Kaya Van Beynen
USF St. Petersburg campus Faculty Publications
Hillsborough County, Florida, is a karst region that is heavily urbanized, yet no study has been undertaken measuring the degree of human disturbance. Van Beynen and Townsend (2005) created a hierarchical and standardized disturbance index specifically designed for karst environments. To address the problem of determining human disturbance in the county, the above index was successfully applied and it was found that Hillsborough was highly disturbed (disturbance score of 0.69 of 1.0) because of its predominant urban and rural land use. Furthermore, the application of the index allowed for its refinement and the highlighting of environmental aspects in need of …
A Disturbance Instance For Karst Environments., Philip Van Beynen, Kaya Van Beynen
A Disturbance Instance For Karst Environments., Philip Van Beynen, Kaya Van Beynen
USF St. Petersburg campus Faculty Publications
Karst environments, unique from other environments, require their own disturbance index. Karst resources are increasingly disturbed by a variety of processes related to social, physical, and economic factors. Recent studies have begun to qualify and quantify these disturbances, yet their focus has been limited to one or two factors such as biotic, geomorphic, or economic impacts. A more holistic approach, addressing economic, scientific, and cultural factors, is needed, to effectively assess the threats to karst areas. Currently, there is no efficient method to measure, compare, and contrast the disturbance of karst environments. We propose a hierarchal and standardized environmental disturbance …